While the attention is focused on the the Indian election, a few authoritative online magazines have written on the Indus Valley Civilization (of which the main city were Mohenjo Daro and Harappa), which has not been fully deciphered yet. The main issues are: was the civilization written, and therefore had a literate culture? Are the signs on seals symbols only, or characters of a script? Is there any link between Harappan and Vedic cultures?
I want to point out two articles because the first one is published on Wired, the famous tech magazine, and the second is a sort of summary of the whole debate and is published on Asia Times. We cannot but agree with Raja Murthy, the author of the last article, who writes:
If the Indus Valley has an equivalent to the sensational 18th-century discovery of the Rosetta Stone, considered one of the greatest-ever historical finds, that would indeed confirm whether the Indus symbols are a written language - one possibly opening the doorway to an unknown civilization. [...]
Dating to 196 BC and displayed in the British Museum since 1802, the Rosetta plaque carried a royal decree in Egyptian and Greek in three scripts - Hieroglyphic, Demotic Egyptian and Greek. Since Greek was a known language, stunned scholars could use the translation to decipher the 3,500-year-old hieroglyphics. The doorway to ancient Egypt was opened to the modern world.
Even if the Indus Valley symbols are indeed a written script, there is little chance of deciphering them unless a Rosettta Stone equivalent is available. Archaeologists from India and Pakistan continue to work at Indus Valley sites, unearthing new discoveries each year.